It is generally accepted in physics and chemistry that the universe is made up of a number of stable and less stable elements ranging in progressive units of atomic masses. The periodic law states that the properties of the chemical elements and their compounds are a periodic function of their atomic number. The periodic table is a table of the elements written in sequence in the order of atomic number and arranged in horizontal rows (periods) and vertical columns (groups) to illustrate the occurrence of similarities in the properties of the elements as a periodic function of the sequence. Present versions of the table used in texts have remained essentially unchanged for the past fifty years, except for the addition of new elements.
Every chemistry laboratory and classroom has a periodic table displayed. It can be difficult, however, to engage students to learn about the elements with a conventional periodic table. Also, the significance of the natural grouping of elements shown by the periodic table may be lost on many students, and some heavier elements might be completely ignored. Therefore a periodic table of the elements and a method of learning about the elements that engage students to learn about the elements, including the most unusual of them, and that helps students see the groupings of the elements within the table are needed.
U.S. Pat. No. 3,581,409, by Roy H. Alexander teaches a three dimensional symbolic representation of the elements with fully grouped families including the Rare Earth series is presented in which the symbolic representations of the elements are arranged contiguously and continuously according to the atomic number. Alexander teaches an arrangement of the elements that includes a single three dimensional form with the elements arranged according to atomic number and without interruption of the atomic number. Therefore a three dimensional representation of the elements with multiple three dimensional forms to be assembled and which challenges a student to thereby encourage learning about the elements is needed.
U.S. Pat. No. 4,199,876, by Gerson Katz teaches a device for displaying a periodic table of the chemical elements. Katz's table includes four detachable, coaxially mounted cylinders. Each cylinder is divided into an upper cylindrical section and a lower cylindrical section. The sections are also detachably mounted. The upper surfaces of each of the cylindrical sections are marked with discrete sectors containing indicia that denote the chemical elements. The device can also be used to determine n and 1 numbers of quantum theory for selected elements. An aid that has a transverse surface marked to correspond to the discrete sectors on the upper surfaces of the cylindrical sections is used to determine ml and ms numbers of quantum theory for selected elements. A second device for displaying the periodic table of the elements is in the form of four detachable, concentrically mounted spheres. The surface of each of the spheres is divided into an upper hemisphere and a lower hemisphere. The hemispheres are preferably detachably mounted. The outer surface of each of the hemispheres is marked with discrete sectors containing indicia that denote the chemical elements. The tables taught by Katz do not readily depict the natural groupings of the elements, such as the transition metals and alkaline groups. Further, since the spheres taught by Katz are concentrically mounted, the inner spheres are at least partially concealed by the outer spheres. Therefore an improved three dimensional periodic table that readily displays the natural groupings of the elements and which does not conceal information about any of the elements is needed.